Mohammad Reza Rohani - Department of Chemical Engineering, Payam Noor University, Tehran, Iran

During curing unsaturated polyester (UP) resin, a high polymerization shrinkage (about 7-10%) is created by free radical copolymerization of unsaturated polyester resin and styrene monomer. The volume shrinkage causes warping, wavy surfaces, internal voids and cracks. Anti-shrinkage is essential to the UP resin and the composite materials of UPR matrix. Thermoplastic materials as low profile additives (LPAs) have been found very effective in controlling volume shrinkage of cured UP resins. By using organically modified clay in UP/LPA Nano-composites a developed type of composite is created which leads to more effect on shrinkage control in UP/LPA system. This study tries to explain the mechanism of curing shrinkage and the effect of both LPA and organically modified clay on shrinkage control.

Unsaturated polyester resin, Shrinkage control, Low profile additives (LPAs), Nano composites